#include <iostream>
#include<math.h>
using namespace std;
int main()
{
    int n,p;float y;
    cout<<"n=";cin>>n;
    p=ceil(n/4);
    switch(p)
    {
        case 1:y=1.0;break;
        case 2:y=1.5;break;
        case 3:y=2.0;break;
        case 4:y=2.5;break;


    }
    if(n==12) y=2.5;
    if(n<=0) y=1;
    cout<<"\ny="<<y<<endl;
    return 0;
}